Efrotomycin is an antibiotic isolated from the fermentation broth of Streptomyces lactamdurans and is disclosed in U.S. Pat. No. 4,024,251. Other antibiotics of related structure are also disclosed such as mocimycin, dihydromocimycin, aurodox, heneicomycin, kirrothricin and the like. The compounds are realized in the following formula: ##STR1## For efrotomycin R.sub.1 is methyl, R.sub.3 is hydroxy and R.sub.2 is: ##STR2## For mocimycin R.sub.1 and R.sub.2 are hydrogen and R.sub.3 is hydroxy; for dihydromocimycin the 5,6-double bond is reduced; for aurodox R.sub.1 is methyl, R.sub.2 is hydrogen and R.sub.3 is hydroxy; for heneicomycin R.sub.1 is methyl, R.sub.2 and R.sub.3 are hydrogen; and for kirrothricin R.sub.1 is methyl, R.sub.2 and R.sub.3 are hydrogen and the furan ring at the 14-17 positions is replaced by ##STR3##
All the compounds have antimicrobial and growth promotion activity. See "The Chemistry of Aurodox and Related Antibiotics." by Maehr et al. in Canadian Journal of Chemistry 58, page 501 (1980). Since Maehr et al. has the structure of kirrothricin listed incorrectly, reference is made to "Metabolic Products of Microorganisms, Kirrothricin," by Thien-Schranner et al., in the Journal of Antibiotics XXXV, page 948, (1982).